#ifndef _NUMBER_DETECTOR_HPP
#define _NUMBER_DETECTOR_HPP
#include "opencv2/core/core.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"

#include <iostream>
#include <math.h>
#include <string.h>

class NumberArea{
public:
    int number;
    int x;
    int y;
    cv::Mat image;
};

using namespace cv;
using namespace std;
class NumberDetector{
public:
    int thresh = 50, N = 5;

    double angle( Point pt1, Point pt2, Point pt0 )
    {
        double dx1 = pt1.x - pt0.x;
        double dy1 = pt1.y - pt0.y;
        double dx2 = pt2.x - pt0.x;
        double dy2 = pt2.y - pt0.y;
        return (dx1*dx2 + dy1*dy2)/sqrt((dx1*dx1 + dy1*dy1)*(dx2*dx2 + dy2*dy2) + 1e-10);
    }

    // 找数字区域的四个角
    void findSquares( const Mat& image, vector<vector<Point> >& squares )
    {
        squares.clear();

    //s    Mat pyr, timg, gray0(image.size(), CV_8U), gray;

        // down-scale and upscale the image to filter out the noise
        //pyrDown(image, pyr, Size(image.cols/2, image.rows/2));
        //pyrUp(pyr, timg, image.size());


        // blur will enhance edge detection
        Mat timg(image);
        medianBlur(image, timg, 9);
        Mat gray0(timg.size(), CV_8U), gray;

        vector<vector<Point> > contours;

        // find squares in every color plane of the image
        for( int c = 0; c < 3; c++ )
        {
            int ch[] = {c, 0};
            mixChannels(&timg, 1, &gray0, 1, ch, 1);

            // try several threshold levels
            for( int l = 0; l < N; l++ )
            {
                // hack: use Canny instead of zero threshold level.
                // Canny helps to catch squares with gradient shading
                if( l == 0 )
                {
                    // apply Canny. Take the upper threshold from slider
                    // and set the lower to 0 (which forces edges merging)
                    Canny(gray0, gray, 5, thresh, 5);
                    // dilate canny output to remove potential
                    // holes between edge segments
                    dilate(gray, gray, Mat(), Point(-1,-1));
                }
                else
                {
                    // apply threshold if l!=0:
                    //     tgray(x,y) = gray(x,y) < (l+1)*255/N ? 255 : 0
                    gray = gray0 >= (l+1)*255/N;
                }

                // find contours and store them all as a list
                findContours(gray, contours, RETR_LIST, CHAIN_APPROX_SIMPLE);

                vector<Point> approx;

                // test each contour
                for( size_t i = 0; i < contours.size(); i++ )
                {
                    // approximate contour with accuracy proportional
                    // to the contour perimeter
                    approxPolyDP(Mat(contours[i]), approx, arcLength(Mat(contours[i]), true)*0.02, true);

                    // square contours should have 4 vertices after approximation
                    // relatively large area (to filter out noisy contours)
                    // and be convex.
                    // Note: absolute value of an area is used because
                    // area may be positive or negative - in accordance with the
                    // contour orientation
                    if( approx.size() == 4 &&
                        fabs(contourArea(Mat(approx))) > 3000 &&
                        isContourConvex(Mat(approx)) )
                    {
                        double maxCosine = 0;

                        for( int j = 2; j < 5; j++ )
                        {
                            // find the maximum cosine of the angle between joint edges
                            double cosine = fabs(angle(approx[j%4], approx[j-2], approx[j-1]));
                            maxCosine = MAX(maxCosine, cosine);
                        }

                        // if cosines of all angles are small
                        // (all angles are ~90 degree) then write quandrange
                        // vertices to resultant sequence
                        if( maxCosine < 0.3 )
                            squares.push_back(approx);
                    }
                }
            }
        }
    }

    void drawSquares( Mat& image, const vector<vector<Point> >& squares )
    {
        for( size_t i = 0; i < squares.size(); i++ )
        {
            const Point* p = &squares[i][0];

            int n = (int)squares[i].size();
            //dont detect the border
            if (p-> x > 3 && p->y > 3)
            polylines(image, &p, &n, 1, true, Scalar(0,255,0), 3, LINE_AA);
        }

        const char* wndname = "Square Detection Demo";
        imshow(wndname, image);
    }

    // 获取数字所在的区域，并将它转换成规则的矩形
    void getNumberArea(cv::Mat& image, vector<vector<Point>>& squares, std::vector<NumberArea>& results){
        // std::cout << "raw squares: " << squares.size() << std::endl;
        std::vector<cv::Point> centers;
        auto getCenter = [&](std::vector<cv::Point>& square){
            cv::Point center;
            for(auto point : square){
                center.x += point.x;
                center.y += point.y;
            }
            center.x /= square.size();
            center.y /= square.size();
            return center;
        };
        std::vector<std::vector<cv::Point>> new_squares;
        for(auto points : squares){
            bool is_same = false;
            if(new_squares.empty())
                new_squares.push_back(points);
            else{
                for(auto square : new_squares){
                    auto current_center = getCenter(points);
                    auto last_center = getCenter(square);
                    float thres = 50;
                    if(fabs(current_center.x - last_center.x) < thres
                        && fabs(current_center.y - last_center.y) < thres){
                        is_same = true;
                        break;
                    }
                }
                if(!is_same){
                    new_squares.push_back(points);
                }
            }
        }
        /////////////////////
        // 画出矩形
        // drawSquares(image, new_squares);

        //////// 将不规则四边形投影为矩形，用于做模板匹配
        // std::cout << "new_squares: " << new_squares.size() << std::endl;
        for(auto points : new_squares){
            cv::Rect rect = cv::boundingRect(points);

            cv::Point2f dst_corner[4], src_corners[4];            

            auto center = getCenter(points);
            for(auto point : points){
                if(point.x < center.x && point.y < center.y){
                    src_corners[0].x = point.x - rect.x;
                    src_corners[0].y = point.y - rect.y;
                }
                else if(point.x > center.x && point.y < center.y){
                    src_corners[1].x = point.x - rect.x;
                    src_corners[1].y = point.y - rect.y;
                }
                else if(point.x > center.x && point.y > center.y){
                    src_corners[2].x = point.x - rect.x;
                    src_corners[2].y = point.y - rect.y;
                }
                else if(point.x < center.x && point.y > center.y){
                    src_corners[3].x = point.x - rect.x;
                    src_corners[3].y = point.y - rect.y;
                }
            }
            
            dst_corner[0].x = 0;
            dst_corner[0].y = 0;
            dst_corner[1].x = rect.width;
            dst_corner[1].y = 0; 
            dst_corner[2].x = rect.width;
            dst_corner[2].y = rect.height;
            dst_corner[3].x = 0;
            dst_corner[3].y = rect.height;
            //计算转换矩阵
            cv::Mat H = cv::getPerspectiveTransform(src_corners, dst_corner);
            //对图象进行校正
            cv::Mat dst;

            // 选择数字区域
            cv::Mat src = image(rect);
            cv::warpPerspective(src, dst, H, src.size());

            cv::resize(dst, dst, cv::Size(350, 460));

            NumberArea area;
            area.image = dst;
            area.x = rect.x;
            area.y = rect.y;
            results.push_back(area);

        }
    }
};

#endif

